Characterization of aluminum according to the chemistry plan. Characteristics of aluminum. Aluminum: general characteristics

Obtaining potassium alum

Aluminum(lat. Aluminum), - in the periodic table aluminum is in the third period, in the main subgroup of the third group. Core Charge +13. Electronic structure of the atom 1s 2 2s 2 2p 6 3s 2 3p 1. The metal atomic radius is 0.143 nm, the covalent one is 0.126 nm, the conventional radius of the Al 3+ ion is 0.057 nm. Ionization energy Al - Al + 5.99 eV.

The most typical oxidation state of the aluminum atom is +3. A negative oxidation state is rare. There are free d-sublevels in the outer electron layer of the atom. Due to this, its coordination number in the compounds can be equal not only to 4 (AlCl 4-, AlH 4-, aluminosilicates), but also 6 (Al 2 O 3, 3+).

Historical reference... The name Aluminum comes from lat. alumen - as early as 500 BC. called aluminum alum, which was used as a mordant for dyeing fabrics and for tanning leather. The Danish scientist H. K. Oersted in 1825, acting with potassium amalgam on anhydrous AlCl 3 and then distilling off the mercury, obtained relatively pure aluminum. The first industrial method for the production of aluminum was proposed in 1854 by the French chemist A.E. Saint-Clair Deville: the method consisted in the reduction of double aluminum chloride and sodium Na 3 AlCl 6 with metallic sodium. Similar in color to silver, Aluminum was at first very expensive. From 1855 to 1890, only 200 tons of Aluminum were produced. The modern method of obtaining aluminum by electrolysis of cryolite-alumina melt was developed in 1886 simultaneously and independently of each other by Charles Hall in the USA and P. Héroux in France.

Being in nature

Aluminum is the most abundant metal in the earth's crust. It accounts for 5.5-6.6 mol. share% or 8 wt.%. Its main mass is concentrated in aluminosilicates. Clay is an extremely common product of destruction of rocks formed by them, the main composition of which corresponds to the formula Al 2 O 3. 2SiO 2. 2H 2 O. Of other natural forms of aluminum, bauxite Al 2 O 3 is of the greatest importance. xH 2 O and minerals corundum Al 2 O 3 and cryolite AlF 3. 3NaF.

Receiving

At present, in the industry, aluminum is obtained by electrolysis of a solution of alumina Al 2 O 3 in molten cryolite. Al 2 O 3 must be sufficiently pure, since impurities are removed from the smelted aluminum with great difficulty. The melting point of Al 2 O 3 is about 2050 o C, and that of cryolite is 1100 o C. A molten mixture of cryolite and Al 2 O 3 is subjected to electrolysis, containing about 10 wt% Al 2 O 3, which melts at 960 o C and has electrical conductivity , density and viscosity, the most favorable for the process. With the addition of AlF 3, CaF 2 and MgF 2, electrolysis is possible at 950 ° C.

An electrolyzer for smelting aluminum is an iron casing lined with refractory bricks from the inside. Its bottom (under), collected from blocks of compressed coal, serves as a cathode. The anodes are located on top: these are aluminum frames filled with coal briquettes.

Al 2 O 3 = Al 3+ + AlO 3 3-

Liquid aluminum is released at the cathode:

Al 3+ + 3е - = Al

Aluminum is collected at the bottom of the furnace, from where it is periodically tapped. Oxygen is released at the anode:

4AlO 3 3- - 12е - = 2Al 2 O 3 + 3O 2

Oxygen oxidizes graphite to carbon oxides. As the carbon burns, the anode grows.

Aluminum, in addition, is used as an alloying addition to many alloys to give them heat resistance.

Physical properties of aluminum... Aluminum combines a very valuable set of properties: low density, high thermal and electrical conductivity, high plasticity and good corrosion resistance. It lends itself easily to forging, stamping, rolling, drawing. Aluminum is well welded by gas, resistance and other types of welding. The lattice of Aluminum is cubic face-centered with a parameter a = 4.0413 Å. The properties of aluminum, like all metals, therefore, the degree depends on its purity. Properties of high purity Aluminum (99.996%): density (at 20 ° C) 2698.9 kg / m 3; t pl 660.24 ° C; t bale about 2500 ° С; thermal expansion coefficient (from 20 ° to 100 ° С) 23.86 · 10 -6; thermal conductivity (at 190 ° C) 343 W / mK, specific heat (at 100 ° C) 931.98 J / kgK. ; electrical conductivity with respect to copper (at 20 ° C) 65.5%. Aluminum has low strength (ultimate strength 50–60 MN / m 2), hardness (170 MN / m 2 according to Brinell) and high plasticity (up to 50%). During cold rolling, the tensile strength of Aluminum increases to 115 MN / m 2, the hardness - up to 270 MN / m 2, the elongation decreases to 5% (1 MN / m 2 and 0.1 kgf / mm 2). Aluminum is highly polished, anodized and has a high reflectivity, close to silver (it reflects up to 90% of the incident light energy). Possessing a high affinity for oxygen, aluminum in air is covered with a thin but very strong oxide film Al 2 O 3, which protects the metal from further oxidation and determines its high anticorrosive properties. The strength of the oxide film and protective action it is greatly reduced in the presence of impurities of mercury, sodium, magnesium, copper, etc. Aluminum is resistant to atmospheric corrosion, sea and fresh water, practically does not interact with concentrated or highly diluted nitric acid, organic acids, food.

Chemical properties

When finely crushed aluminum is heated, it burns vigorously in air. Its interaction with sulfur proceeds in a similar way. With chlorine and bromine, the compound occurs already at ordinary temperature, with iodine - when heated. At very high temperatures, aluminum also combines directly with nitrogen and carbon. On the contrary, it does not interact with hydrogen.

Aluminum is quite resistant to water. But if the protective effect of the oxide film is removed mechanically or by amalgamation, then an energetic reaction occurs:

Strongly diluted, as well as very concentrated HNO3 and H2SO4 have almost no effect on aluminum (in the cold), while at medium concentrations of these acids, it gradually dissolves. Pure aluminum is quite stable with respect to hydrochloric acid, but ordinary technical metal dissolves in it.

Under the action of aqueous solutions of alkalis on aluminum, the oxide layer dissolves, and aluminates are formed - salts containing aluminum as part of the anion:

Al 2 O 3 + 2NaOH + 3H 2 O = 2Na

Aluminum, devoid of a protective film, interacts with water, displacing hydrogen from it:

2Al + 6H 2 O = 2Al (OH) 3 + 3H 2

The resulting aluminum hydroxide reacts with an excess of alkali to form a hydroxoaluminate:

Al (OH) 3 + NaOH = Na

The overall equation for the dissolution of aluminum in an aqueous solution of alkali:

2Al + 2NaOH + 6H 2 O = 2Na + 3H 2

Aluminum dissolves noticeably in solutions of salts that, due to their hydrolysis, have an acidic or alkaline reaction, for example, in a solution of Na 2 CO 3.

In the series of stresses, it is located between Mg and Zn. In all its stable compounds, aluminum is trivalent.

The combination of aluminum with oxygen is accompanied by a tremendous release of heat (1676 kJ / mol Al 2 O 3), much more than that of many other metals. In view of this, when a mixture of an oxide of the corresponding metal with aluminum powder is heated, a violent reaction occurs, leading to the release of free metal from the taken oxide. The method of reduction using Al (alumothermy) is often used to obtain a number of elements (Cr, Mn, V, W, etc.) in a free state.

Alumothermia is sometimes used to weld individual steel parts, in particular, the joints of tram rails. The mixture used ("termite") usually consists of fine powders of aluminum and Fe 3 O 4. It is ignited with a fuse made from a mixture of Al and BaO 2. The main reaction goes according to the equation:

8Al + 3Fe 3 O 4 = 4Al 2 O 3 + 9Fe + 3350 kJ

Moreover, a temperature of about 3000 o C. develops.

Aluminum oxide is a white, very refractory (mp 2050 o C) and water-insoluble mass. Natural Al 2 O 3 (corundum mineral), as well as artificially obtained and then strongly calcined, is characterized by high hardness and insolubility in acids. Al 2 O 3 (so-called alumina) can be converted into a soluble state by fusion with alkalis.

Usually, natural corundum contaminated with iron oxide, due to its extreme hardness, is used for the manufacture of grinding wheels, stones, etc. In a finely crushed form, it, called emery, is used for cleaning metal surfaces and making sandpaper. For the same purposes, Al 2 O 3, obtained by fusing bauxite (technical name - alund), is often used.

Transparent colored crystals of corundum - red ruby - admixture of chromium - and blue sapphire - admixture of titanium and iron - precious stones. They are also obtained artificially and used for technical purposes, for example, for the manufacture of parts of precision instruments, stones in watches, etc. Crystals of rubies containing a small impurity of Cr 2 O 3 are used as quantum generators - lasers that create a directed beam of monochromatic radiation.

Due to the insolubility of Al 2 O 3 in water, the hydroxide Al (OH) 3 corresponding to this oxide can be obtained only indirectly from salts. The preparation of hydroxide can be represented as the following scheme. Under the action of alkalis with OH - ions, 3+ water molecules are gradually replaced in aquocomplexes:

3+ + OH - = 2+ + H 2 O

2+ + OH - = + + H 2 O

OH - = 0 + H 2 O

Al (OH) 3 is a bulky gelatinous sediment white, practically insoluble in water, but easily soluble in acids and strong alkalis. It therefore has an amphoteric character. However, its basic and especially acidic properties are rather weakly expressed. In excess of NH 4 OH, aluminum hydroxide is insoluble. One of the forms of dehydrated hydroxide, alumogel, is used in technology as an adsorbent.

When interacting with strong alkalis, the corresponding aluminates are formed:

NaOH + Al (OH) 3 = Na

Aluminates of the most active monovalent metals are readily soluble in water, but due to strong hydrolysis, their solutions are stable only in the presence of a sufficient excess of alkali. Aluminates produced from weaker bases are hydrolyzed in solution almost completely and therefore can only be obtained dry (by fusing Al 2 O 3 with the oxides of the corresponding metals). Meta-aluminates are formed, which in their composition are produced from meta-aluminum acid HAlO 2. Most of them are insoluble in water.

Al (OH) 3 forms salts with acids. The derivatives of most strong acids are readily soluble in water, but they are quite significantly hydrolyzed, and therefore their solutions show an acidic reaction. Soluble salts of aluminum and weak acids are hydrolyzed even more strongly. Due to hydrolysis, sulfide, carbonate, cyanide and some other aluminum salts cannot be obtained from aqueous solutions.

In an aqueous medium, the Al 3+ anion is directly surrounded by six water molecules. Such a hydrated ion is somewhat dissociated according to the following scheme:

3+ + H 2 O = 2+ + OH 3 +

Its dissociation constant is 1. 10 -5, i.e. it is a weak acid (similar in strength to acetic acid). The octahedral environment of Al 3+ by six water molecules is also retained in crystalline hydrates of a number of aluminum salts.

Aluminosilicates can be considered as silicates in which part of the silicon-oxygen tetrahedra SiO 4 4 is replaced by alumino-oxygen tetrahedra AlO 4 5- Of the aluminosilicates, feldspars are the most common, which account for more than half of the mass of the earth's crust. Their main representatives are minerals.

orthoclase K 2 Al 2 Si 6 O 16 or K 2 O. Al 2 O 3. 6SiO 2

albite Na 2 Al 2 Si 6 O 16 or Na 2 O. Al 2 O 3. 6SiO 2

anorthite CaAl 2 Si 2 O 8 or CaO. Al 2 O 3. 2SiO 2

Minerals of the mica group are very common, for example muscovite Kal 2 (AlSi 3 O 10) (OH) 2. Big practical significance has the mineral nepheline (Na, K) 2, which is used to obtain alumina soda products and cement. This production consists of the following operations: a) nepheline and limestone are sintered in tube furnaces at 1200 ° C:

(Na, K) 2 + 2CaCO 3 = 2CaSiO 3 + NaAlO 2 + KAlO 2 + 2CO 2

b) the resulting mass is leached with water - a solution of sodium and potassium aluminates and CaSiO 3 sludge is formed:

NaAlO 2 + KAlO 2 + 4H 2 O = Na + K

c) the CO 2 formed during sintering is passed through the aluminate solution:

Na + K + 2CO 2 = NaHCO 3 + KHCO 3 + 2Al (OH) 3

d) by heating Al (OH) 3, alumina is obtained:

2Al (OH) 3 = Al 2 O 3 + 3H 2 O

e) by evaporation of the mother liquor, soda and potage are released, and the previously obtained sludge is used for the production of cement.

In the production of 1 ton of Al 2 O 3, 1 ton of soda products and 7.5 ton of cement are obtained.

Some aluminosilicates have a loose structure and are capable of ion exchange. Such silicates - natural and especially artificial - are used for water softening. In addition, due to their highly developed surface, they are used as catalyst carriers, i. E. as materials impregnated with a catalyst.

Aluminum halides under normal conditions are colorless crystalline substances. In the series of aluminum halides, AlF 3 differs greatly in properties from its counterparts. It is refractory, slightly soluble in water, chemically inactive. The main method for producing AlF 3 is based on the action of anhydrous HF on Al 2 O 3 or Al:

Al 2 O 3 + 6HF = 2AlF 3 + 3H 2 O

Compounds of aluminum with chlorine, bromine and iodine are low-melting, highly reactive and readily soluble not only in water, but also in many organic solvents. The interaction of aluminum halides with water is accompanied by a significant release of heat. In an aqueous solution, they are all strongly hydrolyzed, but unlike typical acid halides of non-metals, their hydrolysis is incomplete and reversible. Already noticeably volatile under normal conditions, AlCl 3, AlBr 3 and AlI 3 smoke in humid air (due to hydrolysis). They can be obtained by direct interaction of simple substances.

The vapor densities of AlCl 3, AlBr 3 and AlI 3 at relatively low temperatures more or less accurately correspond to the double formulas - Al 2 Hal 6. The spatial structure of these molecules corresponds to two tetrahedra with a common edge. Each aluminum atom is bonded to four halogen atoms, and each of the central halogen atoms is bonded to both aluminum atoms. Of the two bonds of the central halogen atom, one is donor-acceptor, with aluminum functioning as an acceptor.

With halide salts of a number of monovalent metals, aluminum halides form complex compounds, mainly of the types M 3 and M (where Hal is chlorine, bromine or iodine). The tendency towards addition reactions is generally strongly pronounced for the halides under consideration. This is the reason for the most important technical application of AlCl 3 as a catalyst (in oil refining and in organic syntheses).

Of the fluoroaluminates, Na 3 cryolite has the greatest application (for the production of Al, F 2, enamels, glass, etc.). Industrial production artificial cryolite is based on the treatment of aluminum hydroxide with hydrofluoric acid and soda:

2Al (OH) 3 + 12HF + 3Na 2 CO 3 = 2Na 3 + 3CO 2 + 9H 2 O

Chloro-, bromo- and iodoaluminates are obtained by fusing aluminum trihalides with the corresponding metal halides.

Although aluminum does not chemically interact with hydrogen, aluminum hydride can be obtained indirectly. It is a white amorphous mass of composition (AlH 3) n. Decomposes when heated above 105 ° C with the evolution of hydrogen.

When AlH 3 interacts with basic hydrides in an ethereal solution, hydroaluminates are formed:

LiH + AlH 3 = Li

Hydridoaluminates are white solids. They decompose rapidly with water. They are powerful restorers. They are used (especially Li) in organic synthesis.

Aluminum sulfate Al 2 (SO 4) 3. 18H 2 O is obtained by the action of hot sulfuric acid on alumina or kaolin. It is used for water purification, as well as in the preparation of some types of paper.

Potassium alum KAl (SO 4) 2. 12H 2 O are used in large quantities for tanning leather, as well as in dyeing as a mordant for cotton fabrics. In the latter case, the action of alum is based on the fact that the aluminum hydroxide formed as a result of their hydrolysis is deposited in the fibers of the fabric in a finely dispersed state and, by adsorbing the dye, firmly holds it on the fiber.

Among other aluminum derivatives, mention should be made of its acetate (otherwise - acetic acid salt) Al (CH 3 COO) 3, which is used in dyeing fabrics (as a mordant) and in medicine (lotions and compresses). Aluminum nitrate is readily soluble in water. Aluminum phosphate is insoluble in water and acetic acid, but soluble in strong acids and alkalis.

Aluminum in the body... Aluminum is part of the tissues of animals and plants; in the organs of mammalian animals found from 10 -3 to 10 -5% of aluminum (raw material). Aluminum accumulates in the liver, pancreas, and thyroid glands. In plant products, the aluminum content ranges from 4 mg per 1 kg of dry matter (potatoes) to 46 mg (yellow turnip), in animal products - from 4 mg (honey) to 72 mg per 1 kg of dry matter (beef). In the daily human diet, the aluminum content reaches 35–40 mg. There are known organisms that concentrate aluminum, for example, lycopodiaceae, containing up to 5.3% aluminum in ash, mollusks (Helix and Lithorina), in the ash of which 0.2–0.8% aluminum. Forming insoluble compounds with phosphates, aluminum disrupts plant nutrition (absorption of phosphates by roots) and animals (absorption of phosphates in the intestine).

Aluminum geochemistry... The geochemical features of aluminum are determined by its high affinity for oxygen (in minerals, aluminum is included in oxygen octahedra and tetrahedrons), constant valence (3), and poor solubility of most natural compounds. In endogenous processes during the solidification of magma and the formation of igneous rocks, aluminum enters the crystal lattice of feldspars, micas and other minerals - aluminosilicates. In the biosphere, aluminum is a weak migrant; it is scarce in organisms and the hydrosphere. In humid climates, where the decaying remains of abundant vegetation form many organic acids, aluminum migrates in soils and waters in the form of organomineral colloidal compounds; aluminum is adsorbed by colloids and deposited at the bottom of the soil. The bond of aluminum with silicon is partially broken and in some places in the tropics minerals are formed - aluminum hydroxides - boehmite, diaspora, hydrargillite. Most of the aluminum is included in aluminosilicates - kaolinite, beidellite and other clay minerals. Poor mobility determines the residual accumulation of aluminum in the weathering crust of the humid tropics. As a result, eluvial bauxites are formed. In the past geological epochs, bauxites also accumulated in lakes and the coastal zone of the seas of tropical regions (for example, sedimentary bauxites of Kazakhstan). In the steppes and deserts, where there is little living matter, and the waters are neutral and alkaline, aluminum almost does not migrate. The most vigorous migration of aluminum is in volcanic areas, where strongly acidic river and underground waters rich in aluminum are observed. In places where acidic waters move with alkaline ones - sea ones (at river mouths and others), aluminum is deposited with the formation of bauxite deposits.

Application of Aluminum... The combination of physical, mechanical and chemical properties of aluminum determines its widespread use in almost all areas of technology, especially in the form of its alloys with other metals. In electrical engineering, Aluminum successfully replaces copper, especially in the production of massive conductors, for example, in overhead lines, high-voltage cables, switchgear buses, transformers (the electrical conductivity of Aluminum reaches 65.5% of the electrical conductivity of copper, and it is more than three times lighter than copper; with a cross section providing the same conductivity, the mass of aluminum wires is half that of copper wires). Ultrapure Aluminum is used in the production of electrical capacitors and rectifiers, the action of which is based on the ability of the oxide film of Aluminum to transmit electricity in one direction only. Ultrapure aluminum, purified by zone melting, is used for the synthesis of A III B V type semiconductor compounds used for the production of semiconductor devices. Pure Aluminum is used in the production of all sorts of mirror reflectors. High-purity aluminum is used to protect metal surfaces from atmospheric corrosion (cladding, aluminum paint). With its relatively low neutron absorption cross section, aluminum is used as a structural material in nuclear reactors.

Large-capacity aluminum tanks store and transport liquid gases (methane, oxygen, hydrogen, etc.), nitric and acetic acids, clean water, hydrogen peroxide and edible oils... Aluminum is widely used in equipment and apparatus Food Industry, for food packaging (in the form of foil), for the production of all sorts of household products. The consumption of aluminum for the decoration of buildings, architectural, transport and sports facilities has increased dramatically.

In metallurgy, aluminum (in addition to alloys based on it) is one of the most common alloying additives in alloys based on Cu, Mg, Ti, Ni, Zn, and Fe. Aluminum is also used for deoxidizing steel before pouring it into a mold, as well as in the processes of obtaining some metals by the method of aluminothermy. On the basis of aluminum, by the method of powder metallurgy, SAP (sintered aluminum powder) has been created, which has high heat resistance at temperatures above 300 ° C.

Aluminum is used in the production of explosives (ammonal, alumotol). Widely used various connections Aluminum.

Production and consumption of Aluminum is constantly growing, significantly outstripping the production of steel, copper, lead, zinc in terms of growth rates.

List of used literature

1.V.A. Rabinovich, Z. Ya. Khavin "A Brief Chemical Handbook"

2.L.S. Guzey "Lectures on General Chemistry"

3.N.S. Akhmetov "General and Inorganic Chemistry"

4. B.V. Nekrasov "Textbook of General Chemistry"

5. N.L. Glinka "General chemistry"

It is the most abundant metal in the earth's crust. It belongs to the group of light metals, has a low density and melting point. In this case, plasticity and electrical conductivity are at high level that provides it. So, let's find out what are the specific melting points of aluminum and its alloys (etc. in comparison with and), thermal and electrical conductivity, density, other properties, as well as what are the features of the structure of aluminum alloys and their chemical composition.

To begin with, the structure and chemical composition of aluminum are subject to our consideration. The tensile strength of pure aluminum is extremely low and amounts to 90 MPa. If manganese or magnesium is added to its composition in a small ratio, the strength can increase to 700 MPa. The use of a special heat treatment will lead to the same result.

The metal with the highest purity (99.99% aluminum) can be used for special and laboratory purposes, in other cases with technical purity. The most common impurities in it can be silicon and iron, which practically do not dissolve in aluminum. As a result of their addition, the ductility decreases and the strength of the final metal increases.

The structure of aluminum is represented by unit cells, which in turn consist of four atoms. The theoretical density of this metal is 2698 kg / m 3.

Now let's talk about the properties of aluminum metal.

This video will tell you about the structure of aluminum:

Properties and characteristics

The properties of the metal are its high heat and electrical conductivity, resistance to corrosion, high plasticity and resistance to low temperatures. Moreover, its main property is its low density (about 2.7 g / cm 3.).

Mechanical, technological, as well as physicochemical properties of this metal are directly dependent on its constituent impurities. Its natural components include and.

main parameters

The density of aluminum is 2.7 * 10 3 kg / m 3;
Specific gravity - 2.7 G/ cm 3;
Melting point of aluminum 659 ° C;
Boiling point 2000 ° C;
The coefficient of linear expansion is - 22.9 * 10 6 (1 / deg).

Now the thermal conductivity and electrical conductivity of aluminum are subject to consideration.

This video compares the melting points of aluminum and other commonly used metals:

Electrical conductivity

An important indicator of aluminum is its electrical conductivity, which is second only to gold, silver, etc. The high coefficient of electrical conductivity in combination with low density provides the material with high competitiveness in the field of cabling and wiring.

In addition to the main impurities, this indicator is also influenced by manganese and chromium. If aluminum is intended for the production of current conductors, then the total amount of impurities should not exceed 0.01%.

The conductivity index can vary, depending on the state in which the aluminum is found. The process of prolonged annealing increases this indicator, while work-hardening, on the contrary, decreases it.
Resistivity at a temperature of 20 0 С, depending on the metal grade, is in the range of 0.0277-0.029 μOhm * m.

Thermal conductivity

The thermal conductivity of the metal is about 0.50 cal / cm * s * C and increases with the degree of its purity.

This value is less than that of silver, but more than that of other metals. Thanks to him, aluminum is actively used in the production of heat exchangers and radiators.

Corrosion resistance

The metal itself is a chemically active substance, due to which it is used in aluminothermy. Upon contact with air, it forms the thinnest film of aluminum oxide, which has chemical inertness and high strength. Its main purpose is to protect the metal from the subsequent oxidation process, as well as from the effects of corrosion.

If aluminum is of high purity, then this film has no pores, completely covers its surface and provides reliable adhesion. As a result, the metal is resistant not only to water and air, but also to alkalis and inorganic acids.
Where there are impurities, the protective layer of the film may be damaged. Such places become vulnerable to corrosion. Therefore, pitting corrosion may occur on the surface. If the grade contains 99.7% aluminum and less than 0.25% iron, the corrosion rate is 1.1, with an aluminum content of 99.0% this indicator increases to 31.
The contained iron also reduces the resistance of the metal to alkalis, but does not change the resistance to sulfuric and nitric acids.

Interaction with various substances

When aluminum has a temperature of 100 0 C, it is able to interact with chlorine. Regardless of the degree of heating, aluminum dissolves hydrogen, but does not react with it. That is why it is the main constituent element of the gases that are present in the metal.

In general, aluminum is stable in the following environments:

Fresh and sea water;
Magnesium, sodium and ammonium salts;
Sulphuric acid;
Weak solutions of chromium and phosphorus;
Ammonia solution;
Acetic, malic and other acids.

Aluminum is not resistant:

Sulfuric acid solution;
Hydrochloric acid;
Caustic alkalis and their solution;
Oxalic acid.

Read about the toxicity and environmental friendliness of aluminum below.

The electrical conductivity of copper and aluminum, as well as other comparisons of the two metals, are presented in the table below.

Comparison of characteristics of aluminum and copper

Toxicity

Although aluminum is very common, it is not used in metabolism in any living creature. It has a slight toxic effect, but many of its inorganic compounds, which dissolve in water, are capable of long time stay in this state and negatively affect living organisms. The most toxic substances are acetates, chlorides and nitrates.

According to the standards, the water for household and drinking purposes may contain 0.2-0.5 mg per 1 liter.

Much more useful information about the properties of aluminum contains this video:

(A l), gallium (Ga), indium (In) and thallium (T l).

As you can see from the data provided, all these items were opened in XIX century.

Discovery of metals of the main subgroup III group

V	Al	Ga	In	Tl
1806 g.	1825 g.	1875 g.	1863 g.	1861 g.
G. Lussac,	G.H. Oersted	L. de Boisbaudran	F. Reich,	W. Crookes
L. Tenard	(Denmark)	(France)	I. Richter	(England)
(France)			(Germany)

Boron is a non-metal. Aluminum is a transition metal, while gallium, indium and thallium are high-grade metals. Thus, with an increase in the radii of the atoms of the elements of each group of the periodic table, the metallic properties of simple substances increase.

In this lecture, we will take a closer look at the properties of aluminum.

1. The position of aluminum in the table of D.I.Mendeleev. Atomic structure, exhibited oxidation states.

The aluminum element is located in III group, main "A" subgroup, 3 period of the periodic system, serial number No. 13, relative atomic mass Ar (Al ) = 27. Its neighbor on the left in the table is magnesium - a typical metal, and on the right - silicon - already a non-metal. Consequently, aluminum must exhibit properties of some intermediate character and its compounds are amphoteric.

Al +13) 2) 8) 3, p - element,

Ground state

1s 2 2s 2 2p 6 3s 2 3p 1

Excited state

1s 2 2s 2 2p 6 3s 1 3p 2

Aluminum exhibits an oxidation state of +3 in compounds:

Al 0 - 3 e - → Al +3

2. Physical properties

Free aluminum is a silvery-white metal with high thermal and electrical conductivity.The melting point is 650 o C. Aluminum has a low density (2.7 g / cm 3) - about three times less than that of iron or copper, and at the same time it is a strong metal.

3. Being in nature

In terms of prevalence in nature, it occupies 1st among metals and 3rd among elements, second only to oxygen and silicon. The percentage of aluminum in the earth's crust, according to various researchers, ranges from 7.45 to 8.14% of the mass of the earth's crust.

In nature, aluminum is found only in compounds (minerals).

Some of them:

· Bauxite - Al 2 O 3 H 2 O (with admixtures of SiO 2, Fe 2 O 3, CaCO 3)

· Nepheline - KNa 3 4

· Alunites - KAl (SO 4) 2 2Al (OH) 3

· Alumina (mixtures of kaolin with sand SiO 2, limestone CaCO 3, magnesite MgCO 3)

· Corundum - Al 2 O 3

· Feldspar (orthoclase) - K 2 O × Al 2 O 3 × 6SiO 2

· Kaolinite - Al 2 O 3 × 2SiO 2 × 2H 2 O

· Alunite - (Na, K) 2 SO 4 × Al 2 (SO 4) 3 × 4Al (OH) 3

· Beryl - 3ВеО Al 2 О 3 6SiO 2

Bauxite
Al 2 O 3	Corundum
	Ruby
	Sapphire

4. Chemical properties of aluminum and its compounds

Aluminum easily interacts with oxygen under normal conditions and is covered with an oxide film (it gives a matte look).

OXIDE FILM DEMONSTRATION

Its thickness is 0.00001 mm, but thanks to it, aluminum does not corrode. To study the chemical properties of aluminum, the oxide film is removed. (Using sandpaper, or chemically: first, dipping into an alkali solution to remove the oxide film, and then into a solution of mercury salts to form an alloy of aluminum with mercury - amalgam).

I... Interaction with simple substances

Already at room temperature, aluminum actively reacts with all halogens, forming halides. When heated, it interacts with sulfur (200 ° C), nitrogen (800 ° C), phosphorus (500 ° C) and carbon (2000 ° C), with iodine in the presence of a catalyst - water:

2А l + 3 S = А l 2 S 3 (aluminum sulfide),

2А l + N 2 = 2А lN (aluminum nitride),

A l + P = A l P (aluminum phosphide),

4А l + 3С = А l 4 C 3 (aluminum carbide).

2 Аl +3 I 2 = 2 A l I 3 (aluminum iodide) AN EXPERIENCE

All these compounds are completely hydrolyzed with the formation of aluminum hydroxide and, accordingly, hydrogen sulfide, ammonia, phosphine and methane:

Al 2 S 3 + 6H 2 O = 2Al (OH) 3 + 3H 2 S

Al 4 C 3 + 12H 2 O = 4Al (OH) 3 + 3CH 4

In the form of shavings or powder, it burns brightly in air, giving off a large amount of heat:

4А l + 3 O 2 = 2А l 2 О 3 + 1676 kJ.

COMBUSTION OF ALUMINUM IN AIR

AN EXPERIENCE

II... Interaction with complex substances

Interaction with water :

2 Al + 6 H 2 O = 2 Al (OH) 3 +3 H 2

without oxide film

AN EXPERIENCE

Interaction with metal oxides:

Aluminum is a good reducing agent, as it is one of the active metals. It is in the line of activity right after the alkaline earth metals. That's why restores metals from their oxides ... Such a reaction - alumothermy - is used to obtain pure rare metals, such as tungsten, vanadium, etc.

3 Fe 3 O 4 +8 Al = 4 Al 2 O 3 +9 Fe + Q

Thermite mixture of Fe 3 O 4 and Al (powder) is also used in thermite welding.

С r 2 О 3 + 2А l = 2С r + А l 2 О 3

5interactions with acids :

With sulfuric acid solution: 2 Al + 3 H 2 SO 4 = Al 2 (SO 4) 3 +3 H 2

Does not react with cold concentrated sulfuric and nitrogenous (passivates). Therefore, nitric acid is transported in aluminum tanks. When heated, aluminum is able to reduce these acids without the evolution of hydrogen:

2А l + 6Н 2 S О 4 (conc) = А l 2 (S О 4) 3 + 3 S О 2 + 6Н 2 О,

A l + 6H NO 3 (conc) = A l (NO 3) 3 + 3 NO 2 + 3H 2 O.

Interaction with alkalis .

2 Al + 2 NaOH + 6 H 2 O = 2 Na [ Al (OH) 4 ] +3 H 2

AN EXPERIENCE

Na[Al(OH) 4] – sodium tetrahydroxoaluminate

At the suggestion of the chemist Gorbov, in Russo-Japanese War this reaction was used to produce hydrogen for balloons.

With salt solutions:

2 Al + 3 CuSO 4 = Al 2 (SO 4) 3 + 3 Cu

If the surface of aluminum is rubbed with mercury salt, then the reaction occurs:

2 Al + 3 HgCl 2 = 2 AlCl 3 + 3 Hg

Released mercury dissolves aluminum to form amalgam .

Detection of aluminum ions in solutions : AN EXPERIENCE

5. Application of aluminum and its compounds

The physical and chemical properties of aluminum have led to its widespread use in technology. The aviation industry is a major consumer of aluminum.: the plane is 2/3 composed of aluminum and its alloys. An airplane made of steel would be too heavy and could carry far fewer passengers. Therefore, aluminum is called a winged metal. Aluminum is used to make cables and wires: with the same electrical conductivity, their mass is 2 times less than the corresponding copper products.

Given the corrosion resistance of aluminum, manufacture parts for devices and containers for nitric acid... Aluminum powder is the basis for the manufacture of silver paint to protect iron products from corrosion, as well as to reflect heat rays with this paint they cover oil storage tanks, firefighters' suits.

Aluminum oxide is used to produce aluminum and also as a refractory material.

Aluminum hydroxide is the main component of the well-known drugs Maalox, Almagel, which lower the acidity of gastric juice.

Aluminum salts are highly hydrolyzed. This property is used in the process of water purification. Aluminum sulfate and a small amount of slaked lime are added to the water to be treated to neutralize the resulting acid. As a result, a bulk precipitate of aluminum hydroxide is released, which, when settling, carries away suspended particles of turbidity and bacteria.

Thus, aluminum sulfate is a coagulant.

6. Obtaining aluminum

1) The modern cost-effective method of producing aluminum was invented by the American Hall and the Frenchman Eroux in 1886. It consists in the electrolysis of a solution of aluminum oxide in molten cryolite. Molten cryolite Na 3 AlF 6 dissolves Al 2 O 3 like water dissolves sugar. The electrolysis of the “solution” of alumina in molten cryolite occurs as if cryolite was only a solvent, and alumina was an electrolyte.

2Al 2 O 3 electric current → 4Al + 3O 2

In the English Encyclopedia for Boys and Girls, an article about aluminum begins with the following words: “On February 23, 1886, a new metal age began in the history of civilization - the age of aluminum. On this day, Charles Hall, a 22-year-old chemist, came to his first teacher's laboratory with a dozen small balls of silvery-white aluminum in his hand and with the news that he had found a way to make this metal cheaply and in large quantities. " Thus Hall became the founder of the American aluminum industry and the Anglo-Saxon national hero, as a man who made a great business out of science.

2) 2Al 2 O 3 +3 C = 4 Al + 3 CO 2

IT IS INTERESTING:

Metallic aluminum was first isolated in 1825 by the Danish physicist Hans Christian Oersted. Skipping chlorine gas through a layer of red-hot aluminum oxide mixed with coal, Oersted released aluminum chloride without the slightest trace of moisture. To restore metallic aluminum, Oersted needed to treat aluminum chloride with potassium amalgam. After 2 years, the German chemist Friedrich Wöller. He improved the method by replacing the potassium amalgam with pure potassium.
In the 18th and 19th centuries, aluminum was the main jewelry metal. In 1889, D.I. Mendeleev in London for his merits in the development of chemistry was awarded a valuable gift- weights made of gold and aluminum.
By 1855, the French scientist Saint-Clair Deville had developed a method for producing metallic aluminum on a technical scale. But the method was very expensive. Deville enjoyed the special patronage of Napoleon III, Emperor of France. As a token of his devotion and gratitude, Deville made for Napoleon's son, the newborn prince, an exquisitely engraved rattle - the first "consumer goods" made of aluminum. Napoleon even intended to equip his guardsmen with aluminum cuirass, but the price turned out to be prohibitive. At that time, 1 kg of aluminum cost 1000 marks, i.e. 5 times more expensive than silver. Only after the invention of the electrolytic process did aluminum become equal in cost to conventional metals.
Did you know that when aluminum enters the human body, it causes a disorder of the nervous system. With its excess, metabolism is disturbed. A protective equipment is vitamin C, a compound of calcium, zinc.
When aluminum burns in oxygen and fluorine, a lot of heat is released. Therefore, it is used as an additive to rocket fuel. The Saturn rocket burns 36 tons of aluminum powder during the flight. The idea of using metals as a component of rocket fuel was first expressed by F. A. Tsander.

SIMULATORS

Simulator No. 1 - Characteristics of aluminum by position in the Periodic Table of Elements by D. I. Mendeleev

Simulator No. 2 - Equations of reactions of aluminum with simple and complex substances

Simulator No. 3 - Chemical properties of aluminum

ASSIGNMENT TASKS

# 1. To obtain aluminum from aluminum chloride, metallic calcium can be used as a reducing agent. Make an equation for a given chemical reaction, characterize this process using electronic balance.
Think! Why can't this reaction be carried out in aqueous solution?

No. 2. Complete the chemical reaction equations:
Al + H 2 SO 4 (solution ) ->
Al + CuCl 2 ->
Al + HNO 3 ( end ) - t ->
Al + NaOH + H 2 O ->

No. 3. Make transformations:
Al -> AlCl 3 -> Al -> Al 2 S 3 -> Al (OH) 3 - t -> Al 2 O 3 -> Al

No. 4. Solve the problem:
The aluminum-copper alloy was exposed to an excess of concentrated sodium hydroxide solution when heated. Allocated 2.24 liters of gas (n.u.). Calculate the percentage of the alloy if its total weight was 10 g?

Each chemical element can be considered from the point of view of three sciences: physics, chemistry and biology. And in this article we will try to characterize aluminum as accurately as possible. It is a chemical element in the third group and third period, according to the periodic table. Aluminum is a metal with average chemical activity. Also, amphoteric properties can be observed in its compounds. The atomic mass of aluminum is twenty-six grams per mole.

Physical characteristics of aluminum

Under normal conditions, it is a solid. The formula for aluminum is very simple. It consists of atoms (they do not combine into molecules), which are lined up with the help of a crystal lattice into a continuous substance. Aluminum color - silvery white. In addition, it has a metallic luster, like all other substances in this group. The color of aluminum used in industry can be different due to the presence of impurities in the alloy. It is a fairly light metal.

Its density is 2.7 g / cm3, that is, it is approximately three times lighter than iron. In this it can concede only to magnesium, which is even lighter than the metal in question. The hardness of aluminum is quite low. In it, it is inferior to most metals. The hardness of aluminum is only two. Therefore, to strengthen it, harder ones are added to alloys based on this metal.

Melting of aluminum occurs at a temperature of only 660 degrees Celsius. And it boils when heated to a temperature of two thousand four hundred and fifty-two degrees Celsius. It is a very ductile and low-melting metal. The physical characterization of aluminum does not end there. I would also like to note that this metal has the best electrical conductivity after copper and silver.

Prevalence in nature

Aluminum, specifications which we have just examined is quite common in environment... It can be seen in many minerals. The element aluminum is the fourth most abundant element in nature. Its in the earth's crust is almost nine percent. The main minerals, which contain its atoms, are bauxite, corundum, cryolite. The first is a rock, which consists of oxides of iron, silicon and the metal in question, and water molecules are also present in the structure. It has a non-uniform color: fragments of gray, reddish-brown and other colors, which depend on the presence of various impurities. From thirty to sixty percent of this breed is aluminum, the photo of which can be seen above. In addition, corundum is a very common mineral in nature.

This is aluminum oxide. His chemical formula- Al2O3. It can be red, yellow, blue, or brown... Its hardness on the Mohs scale is nine. The varieties of corundum include well-known sapphires and rubies, leucosapphires, and padparadscha (yellow sapphire).

Cryolite is a mineral with a more complex chemical formula. It consists of aluminum and sodium fluorides - AlF3.3NaF. It looks like a colorless or grayish stone with a low hardness - only three on the Mohs scale. In the modern world, it is synthesized artificially in the laboratory. It is used in metallurgy.

Also, aluminum can be found in nature in the composition of clays, the main components of which are oxides of silicon and the metal in question, associated with water molecules. In addition, this chemical element can be observed in the composition of nephelines, the chemical formula of which is as follows: KNa34.

Receiving

Characterization of aluminum provides for consideration of methods for its synthesis. There are several methods. The production of aluminum by the first method takes place in three stages. The last of these is the electrolysis procedure at the cathode and carbon anode. To carry out such a process, aluminum oxide is required, as well as such Excipients like cryolite (formula - Na3AlF6) and calcium fluoride (CaF2). In order for the process of decomposition of aluminum oxide dissolved in water to take place, it is necessary to heat it together with molten cryolite and calcium fluoride to a temperature of at least nine hundred and fifty degrees Celsius, and then pass through these substances a current of eighty thousand amperes and a voltage of five- eight volts. Thus, due to this process aluminum will settle on the cathode, and oxygen molecules will collect on the anode, which, in turn, oxidize the anode and turn it into carbon dioxide. Before carrying out this procedure, bauxite, in the form of which aluminum oxide is mined, is preliminarily cleaned of impurities, and also undergoes the process of its dehydration.

The production of aluminum by the method described above is very common in metallurgy. There is also a method invented in 1827 by F. Wöhler. It lies in the fact that aluminum can be mined using a chemical reaction between its chloride and potassium. A similar process can be carried out only by creating special conditions in the form of a very high temperature and vacuum. So, from one mole of chloride and the same volume of potassium, one mole of aluminum and three moles as a by-product can be obtained. This reaction can be written in the form of the following equation: АІСІ3 + 3К = АІ + 3КСІ. This method has not gained much popularity in metallurgy.

Characterization of aluminum in terms of chemistry

As mentioned above, this is a simple substance that consists of atoms that are not combined into molecules. Almost all metals form similar structures. Aluminum has a fairly high chemical activity and strong reducing properties. Chemical characterization aluminum will begin with a description of its reactions with other simple substances, and then interactions with complex inorganic compounds will be described.

Aluminum and simple substances

These include, first of all, oxygen - the most common compound on the planet. Twenty one percent of it consists of the Earth's atmosphere. The reactions of a given substance with any others are called oxidation, or combustion. It usually occurs at high temperatures. But in the case of aluminum, oxidation is possible under normal conditions - this is how an oxide film is formed. If this metal is crushed, it will burn, while releasing a large amount of energy in the form of heat. To carry out the reaction between aluminum and oxygen, these components are needed in a molar ratio of 4: 3, as a result of which we obtain two parts of the oxide.

This chemical interaction is expressed as the following equation: 4АI + 3О2 = 2АІО3. Reactions of aluminum with halogens, which include fluorine, iodine, bromine and chlorine, are also possible. The names of these processes come from the names of the corresponding halogens: fluorination, iodination, bromination and chlorination. These are typical addition reactions.

For example, we will give the interaction of aluminum with chlorine. This kind of process can only happen in the cold.

So, taking two moles of aluminum and three moles of chlorine, we will receive as a result two moles of chloride of the metal in question. The equation for this reaction is as follows: 2AI + 3CI = 2AICI3. In the same way, you can get aluminum fluoride, its bromide and iodide.

The substance in question reacts with sulfur only when heated. To carry out the interaction between these two compounds, you need to take them in molar proportions of two to three, and one part of aluminum sulfide is formed. The reaction equation looks like this: 2Al + 3S = Al2S3.

In addition, at high temperatures, aluminum reacts with carbon, forming carbide, and with nitrogen, forming nitride. The following equations of chemical reactions can be cited as an example: 4АI + 3C = АІ4С3; 2Al + N2 = 2AlN.

Interaction with complex substances

These include water, salts, acids, bases, oxides. Aluminum reacts differently with all these chemical compounds. Let's take a closer look at each case.

Reaction with water

Aluminum interacts with the most common complex substance on Earth when heated. This happens only in the case of preliminary removal of the oxide film. As a result of the interaction, amphoteric hydroxide is formed, and hydrogen is also released into the air. Taking two parts of aluminum and six parts of water, we get hydroxide and hydrogen in molar proportions of two to three. The equation of this reaction is written as follows: 2AI + 6H2O = 2AI (OH) 3 + 3H2.

Interaction with acids, bases and oxides

Like other active metals, aluminum is capable of undergoing a substitution reaction. At the same time, it can displace hydrogen from the acid or the cation of a more passive metal from its salt. As a result of such interactions, an aluminum salt is formed, and hydrogen is also released (in the case of an acid) or a pure metal precipitates (the one that is less active than the considered one). In the second case, the reducing properties that were mentioned above are manifested. An example is the interaction of aluminum with which aluminum chloride is formed and hydrogen is released into the air. This kind of reaction is expressed in the form of the following equation: 2AI + 6HCI = 2AICI3 + 3H2.

An example of the interaction of aluminum with a salt can serve as its reaction with Taking these two components, in the end we will get pure copper, which will precipitate. With acids such as sulfuric and nitric, aluminum reacts in a peculiar way. For example, when aluminum is added to a dilute solution of nitrate acid in a molar ratio of eight parts to thirty, eight parts of the nitrate of the metal in question are formed, three parts of nitric oxide and fifteen parts of water. The equation for this reaction is written as follows: 8Al + 30HNO3 = 8Al (NO3) 3 + 3N2O + 15H2O. This process occurs only when there is a high temperature.

If you mix aluminum and weak solution sulfate acid in molar proportions of two to three, then we get the sulfate of the metal in question and hydrogen in a ratio of one to three. That is, an ordinary substitution reaction will occur, as is the case with other acids. For clarity, we present the equation: 2Al + 3H2SO4 = Al2 (SO4) 3 + 3H2. However, with a concentrated solution of the same acid, everything is more complicated. Here, as in the case of nitrate, a by-product is formed, but not in the form of oxide, but in the form of sulfur, and water. If we take the two components we need in a molar ratio of two to four, then as a result we get one part of the salt of the metal in question and sulfur, and four parts of water. This chemical interaction can be expressed using the following equation: 2Al + 4H2SO4 = Al2 (SO4) 3 + S + 4H2O.

In addition, aluminum is capable of reacting with alkali solutions. To carry out such a chemical interaction, you need to take two moles of the metal in question, the same or potassium, as well as six moles of water. As a result, substances such as sodium or potassium tetrahydroxoaluminate are formed, as well as hydrogen, which is released in the form of a gas with a pungent odor in molar proportions of two to three. This chemical reaction can be represented as the following equation: 2AI + 2KON + 6H2O = 2K [AI (OH) 4] + 3H2.

And the last thing to consider is the regularities of the interaction of aluminum with some oxides. The most common and used case is the Beketov reaction. It, like many others discussed above, occurs only at high temperatures. So, for its implementation it is necessary to take two moles of aluminum and one mole of ferrum oxide. As a result of the interaction of these two substances, we obtain aluminum oxide and free iron in an amount of one and two mol, respectively.

The use of the metal in question in industry

Note that the use of aluminum is a very common occurrence. First of all, the aviation industry needs it. Along with here, alloys based on the metal in question are also used. We can say that the average aircraft consists of 50% aluminum alloys, and its engine is 25%. Also, the use of aluminum is carried out in the manufacture of wires and cables due to its excellent electrical conductivity. In addition, this metal and its alloys are widely used in the automotive industry. The bodies of cars, buses, trolley buses, some trams, as well as carriages of ordinary and electric trains are made of these materials.

It is also used for smaller-scale purposes, for example, for the production of packaging for food and other products, dishes. In order to make a silvery paint, you need a powder of the metal in question. This paint is needed in order to protect the iron from corrosion. We can say that aluminum is the second most frequently used metal in industry after ferrum. His connections and he himself are often used in chemical industry... This is due to the special chemical properties of aluminum, including its reducing properties and the amphotericity of its compounds. Hydroxide of the considered chemical element necessary for water purification. In addition, it is used medicinally in the production of vaccines. It can also be found in some types of plastics and other materials.

Role in nature

As already mentioned above, aluminum in a large number contained in the earth's crust. It is especially important for living organisms. Aluminum participates in the regulation of growth processes, forms connective tissue, such as bone, ligamentous and others. Thanks to this microelement, the processes of regeneration of body tissues are carried out faster. Its lack is characterized by the following symptoms: developmental and growth disorders in children, in adults - chronic fatigue, decreased performance, impaired coordination of movements, reduced rates of tissue regeneration, muscle weakening, especially in the limbs. This phenomenon can occur if you consume too few foods containing this microelement.

However, a more common problem is excess aluminum in the body. At the same time, the following symptoms are often observed: nervousness, depression, sleep disturbances, decreased memory, stress resistance, softening of the musculoskeletal system, which can lead to frequent fractures and sprains. With a prolonged excess of aluminum in the body, problems often arise in the work of almost every organ system.

This phenomenon can lead whole line reasons. First of all, it is Scientists have long proven that dishes made of the metal in question are unsuitable for cooking food in it, since at high temperatures some of the aluminum gets into food, and as a result, you consume much more of this trace element than the body needs.

The second reason is the regular use of cosmetics containing the metal in question or its salts. Before using any product, you must carefully read its composition. Cosmetics are no exception.

The third reason is taking medications that contain a lot of aluminum for a long time. As well as improper use of vitamins and food additives, which include this microelement.

Now let's figure out which foods contain aluminum in order to regulate your diet and organize the menu correctly. First of all, these are carrots, processed cheeses, wheat, alum, potatoes. For fruits, avocados and peaches are recommended. It is also rich in aluminum White cabbage, rice, many healing herbs... Also, the cations of the metal in question can be contained in drinking water... To avoid high or low levels of aluminum in the body (however, just like any other trace element), you need to carefully monitor your diet and try to make it as balanced as possible.

Lesson type... Combined.

Tasks:

Educational:

1. To update the knowledge of students about the structure of the atom, the physical meanings of the serial number, group number, period number using the example of aluminum.

2. To form students' knowledge that aluminum in a free state has special, characteristic physical and chemical properties.

Developing:

1. Stimulate interest in the study of science by providing brief historical and scientific reports on the past, present and future of aluminum.

2. Continue the formation of research skills of students when working with literature, performing laboratory work.

3. Expand the concept of amphotericity by revealing the electronic structure of aluminum, the chemical properties of its compounds.

Educational:

1. To foster respect for the environment by providing information on the possible use of aluminum yesterday, today, tomorrow.

2. To form the ability to work in a team for each student, to take into account the opinion of the whole group and defend their own correctly, performing laboratory work.

3. To acquaint students with the scientific ethics, honesty and decency of natural scientists of the past, providing information about the struggle for the right to be the discoverer of aluminum.

RETRIEVE PASSAGE by topic Alkaline and Alkaline Earth M (REPEAT):

What is the number of electrons at the external energy level of alkaline and alkaline earth M?

What products are formed when interacting with sodium or potassium oxygen? (peroxide), is lithium capable of producing peroxide in reaction with oxygen? (no, the reaction produces lithium oxide.)

How are sodium and potassium oxides obtained? (by calcining peroxides with the corresponding Me, Pr: 2Na + Na 2 O 2 = 2Na 2 O).

Do alkali and alkaline earth metals show negative oxidation states? (no, they do not, since they are strong reducing agents.).

How does the radius of an atom change in the main subgroups (top to bottom) of the Periodic Table? (increases), what is it connected with? (with an increase in the number of energy levels).

Which of the studied groups of metals are lighter than water? (in alkaline).

Under what conditions does alkaline earth metals form hydrides? (at high temperatures).

Which substance, calcium or magnesium, reacts more actively with water? (Calcium reacts more actively. Magnesium actively reacts with water only when it is heated to 100 0 С).

How does the solubility of alkaline earth metal hydroxides in water change, ranging from calcium to barium? (water solubility increases).

Tell us about the peculiarities of storing alkali and alkaline earth metals, why are they stored this way? (since these metals are very reactive, they are stored in a container under a layer of kerosene).

CONTROL WORK on the topics alkaline and alkaline earth M:

LESSON OUTCOME (LEARNING NEW MATERIAL):

Teacher: Hello guys, today we turn to the study of the IIIA subgroup. List the elements located in the IIIA subgroup?

Trainees: It includes elements such as boron, aluminum, gallium, indium and thallium.

Teacher: How many electrons do they contain at the external energy level, the oxidation state?

Trainees: Three electrons, oxidation state +3, although for thallium, oxidation state +1 is more stable.

Teacher: The metallic properties of the elements of the boron subgroup are much weaker than those of the elements of the beryllium subgroup. Bohr is not M. Further, within the subgroup, with an increase in the nuclear charge M, the properties are enhanced. Al- already M, but not typical. Its hydroxide has amphoteric properties.

Of the M main subgroup of group III, the most important is aluminum, the properties of which we will study in detail. It is interesting to us because it is a transitional element.